B-CLL is the most common form of leukaemia in Denmark, with more than 250 new cases diagnosed every year. The disease results in accumulation of CD19+CD5+CD23+ lymphocytes in the blood, bone marrow and organs of the patients. B-CLL cells are long-lived, slowly dividing and locked in the G1 phase of the cell cycle. At this time it is unknown how or why B-CLL occurs and no cure is known for B-CLL. The application of more aggressive treatment strategies has been hampered by the inability to identify reproducible and reliable prognostic predictors in patients with poor outcome in this disease. In many patients the diagnosis does not affect morbidity or mortality. Other patients suffer from an incurable cancer that inevitably results in death, regardless of treatment. Until recently this latter group of patients could not be identified at the time of diagnosis. Recently, two studies established the mutational status of immunoglobulin variable region of the heavy chain (Ig VH) genes in B-CLL as independent prognostic markers, within each clinical stage (Damle, et al. & Hamblin, et al.). Patients without somatic hypermutation show much shorter survival than patients with somatic hypermutation. FISH-studies of cytogenetic aberrations in B-CLL established specific abnormalities on chromosomes 11 (ATM), 12 (?), 13 (Leu-1 and -2) and 17 (p53) as independent prognostic markers, within each clinical stage (Dohner, et al.). Very recent studies have demonstrated that independent risk prediction, using a combined analysis of Ig VH gene mutational analysis and cytogenetics, can identify subgroups of B-CLL with median survival ranging from less than 2.5 years to more than 15 years (Krober, et al., Lin, et al., & Oscier, et al.) (see FIG. 1). Since the process of characterising the Ig VH gene mutational status of an individual patient is cumbersome, it is desirable to provide easier tests based on diagnostic markers for use in the differential diagnosis of such cancer patients.